The role of α1-adrenoceptor subtypes in the phasic and tonic responses to phenylephrine in the longitudinal smooth muscle of the rat portal vein

The purpose of this investigation was to determine whether α1-adrenoceptor subtypes (co)exist in the rat portal vein and, if so, whether they could be functionally associated with the phasic and tonic types of contraction as a response to α1-adrenoceptor stimulation by phenylephrine.